Bulldog OAR

Re: slack tending OAR

Gordon,

Why do you think it acts differently on various ropes? Diameter? Construction?

Are the differences significant in that one type of configuration would not work with another type rope? Say Taychon vr. Imori for example?

Tony
 
Re: slack tending OAR

Tony, To have a device release smoothly, on various size and construction of ropes (harder, softer, denser, more supple) and with various weights of the climbers, is a real challenge. With the OAR it is possible to change the roller size and/or add more rack arms. I have found that the 4 arm OAR, with rollers that will accept up to a 1/2" rope size is a good choice for allowing various size rope to work on the same device. The bottom most arm, when pulled down to release, causes the rope to take a bend around the roller above, and however many other chain link pins and rollers which are above. This gives the option of releasing either one or two of the bottom arms to release smoothly with various size/construction/loads.

For DdRT, you actually only need two rack arms for the OAR to function with Tachyon. (see Bings pictures and comments of his two arm OAR on the Arbtalk site, under my "Dogbone" thread). As a result you could choose to only weave the rope on the top two arms DdRT, and leave the bottom two off, or you could weave all four rack arms on the line and then release all three of the bottom arms at once. In this manner you can "tune" the setup of the OAR for various needs.

Gordon
 
Re: slack tending OAR

Paul, what about the heat? how hot does the OAR get on descent for you. Are you descending on your Rocket Line in this video?

I hope to get the black oxide treated links this week.

Thanks, Gordon
 
Re: slack tending OAR

Paul, I just received your package, Thanks, and thanks for the extra pulley!
 
Re: slack tending OAR

I have a CMI left foot ascender, Thanks.
The rope walking system you demonstrate looks pretty neat, I need to try something like that, with the OAR low on the harness, and both hands free.

At one point I made an ascender with a handled OAR for the feet below and another handled OAR for the hands above, connected by a sort of pogo stick between, The idea was for the internal spring to draw up the feet section, and then advance the hand section while standing on the foot section, sort of like human powered inch worm.
 
Re: slack tending OAR

My personal messages are chronically full, it is best if you contact me via email,

I am shipping these later today, two to Paul and one to Bob.
I have had the master swivel links treated with black oxide, sort of like anodizing on aluminum. This will add corrosion resistance. The aluminum arms were water cut. The OAR on the right is set up for use on KM III, and I have used larger links for the connect points. I bored out the hole so that a biner will attach directly to the OAR top and bottom. These ANSI size 80 links are some tough steel, my cobalt drill bit will hardly touch them.

001-8.jpg


I look forward to your comments.

Gordon
 
Re: slack tending OAR

To those who have the OAR, you might give this idea a try also for SRT. This arraignment is inspired by the Hitch Hiker. I have tied a 6mm hitch cord above the OAR and threaded the tails down through both arms of the 2 arm OAR, just behind the two rollers, then formed a stopper knot below the bottom arm.
002-7.jpg
 
Re: slack tending OAR

I have made this multiple anchor OAR. If you anchor at the leftmost anchor point (pictured) it gives the most gripping force and will grip on a KMIII SRT. For larger Dia. rope you can anchor at the rightmost anchor point (inline with the spine) and it grips for use DdRT or SRT. If you want a gripping force somewhere in between then the anchors can be swiveled to meet together halfway.

002-9.jpg
 
Re: slack tending OAR

Made a refinement to the attach point. It has an adjustable anchor point that uses the brass thumb nut to adjust more grip if needed. It will adjust from almost inline with the spine to 3/4" more of mechanical advantage to the gripping power inherent with the OAR. This allows for a fine tuning of the grip depending on the type of rope and the climbers weight.
DSCN0137_zps7c1d0344.jpg
 
Re: slack tending OAR

Contact me via my regular email under my user name.

Thanks, Gordon
 
Re: slack tending OAR, with O-rig

Here is the OAR set up this morning in an O-rig configuration, using the top arm as the prussic friction on the standing part of the rope, the tether allows release from afar if so desired. (thanks to Justin, Thomas, and Brian for their input on this idea)
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